Absorbent articles intended to absorb menstrual blood discharged from a woman's genital organ are typically constructed to include a liquid absorbent layer, a liquid-permeable topsheet covering the skin surface of the liquid absorbent layer, and a liquid-impermeable backsheet covering the garment surface of the liquid absorbent layer, and generally, they are worn with the backsheet adhered to an inner side of a groin piece of an undergarment through a pressure-sensitive adhesive layer.
Generally, an undergarment to be worn by a woman at the period of menstruation can tightly constrict the wearer's body so as to bring the absorbent article into close contact with the wearer's crotch. However, such a tight undergarment may possibly make the wearer feel unpleasant due to excessive pressure on her lower body during wear. This is noticeable in a hot and humid environment such as summer.
Accordingly, it is required not only that the absorbent article to be used at the period of menstruation come into close contact with the wearer's body by a tightening force from the undergarment but also that the absorbent article be so constructed as to be easily deformed by a force that will be applied from the thighs when put in the wearer's crotch for coming into close contact with the vaginal opening and so on.
Japanese Unexamined Utility-Model Publication No. 3-33622 (Patent Publication 1) discloses an absorbent article that can be easily deformed to come into close contact with the vaginal opening.
In this absorbent article, topside compressed grooves are formed in two sides of its skin surface intended to face the wearer's body, while a backside compressed groove is formed in its garment surface intended to face an undergarment to extend rearwardly from the center of the absorbent article at an intermediate position between the topside compressed grooves. When the absorbent article is applied to the wearer's crotch and the wearer's thighs exert a pressure toward the center of the absorbent article, the absorbent article can be deformed such that its central portion is folded at the backside compressed groove to bulge toward the wearer's body with the topside compressed grooves functioning as starting points, whereby the central portion easily comes into close contact with the vaginal opening.
Such an absorbent article having grooves formed in both the skin surface and the garment surface is also disclosed in Japanese Unexamined Patent Publication No. 10-328233 (Patent Publication 2). This absorbent article suitable for nighttime use is elongated and slightly widened at its rear portion. In this absorbent article, topside grooves are formed in the skin surface at two sides of a portion that is intended to face the vaginal opening; and a rear groove is formed in the garment surface while being located rearwardly apart from the topside grooves. With the rear groove provided in a rear portion of the garment surface, the absorbent article applied to the wearer's crotch can be easily deformed to bulge so that its portion having the rear groove can fit in the cleft of the buttocks.
In the absorbent article disclosed in Patent Publication 1, however, the backside compressed groove formed in the garment surface extends at some length rearwardly from the center of the absorbent article. When applied to the wearer's crotch and subjected to a pressure from the thighs, therefore, the absorbent article bulges toward the wearer's body over almost the whole length. Since the absorbent article is so constructed as to be easily folded to decrease its width over almost the whole length, the absorbent article in a folded state is hardly restored to its original flat state, so that the absorbent article cannot be certainly kept in close contact with the vaginal opening and the cleft of the buttocks. Accordingly, it may possibly fail to collect menstrual blood, causing lateral leakage or rearward leakage.
In addition, since the backside compressed groove extends rearwardly from the center of the absorbent article, if the absorbent article is accidentally worn back to front to have its front portion not having the backside compressed groove opposed to the cleft of the buttocks, the absorbent article cannot closely fit into the cleft of the buttocks.
In the absorbent article disclosed in Patent Publication 1, furthermore, since pressure-sensitive adhesive layers for adhering the article to an undergarment are provided only in its front portion, it may possibly be adhered to an undergarment with its rear portion curled up or folded back.
In the elongated absorbent article disclosed in Patent Publication 2, on the other hand, the topside grooves on the skin surface are not located at two sides of the rear groove that is provided in the rear portion of the article. Therefore, pressure acting on the topside grooves from the thighs cannot be transmitted to the rear groove, so that it is difficult to deform the portion having the rear groove to bulge toward the cleft of the buttocks only by pressure from the thighs. That is, this absorbent article is designed to be used in combination with a tight undergarment that is provided centrally of its back body with an elastic member or the like for exerting a strong tightening force on the rear portion of the absorbent article. Accordingly, if a relatively loose undergarment is worn, the portion having the rear groove will be hardly deformed to bulge toward the cleft of the buttocks.
The present invention has been worked out in view of the shortcomings in the prior art set forth above. It is therefore an object of the present invention to provide an absorbent article which can be easily brought into close contact with an area from the vaginal opening to the cleft of the buttocks, wherein when applied a pressure from the thighs, the absorbent article can be locally deformed to bulge toward the cleft of the buttocks without being folded back as a whole.